Defense hawks scored a win last week by securing more cash for the Pentagon in the Senate budget — but that victory could prove short-lived.

Republicans on the Budget Committee voted last week to boost the Pentagon’s budget by $38 billion at the urging of hawks like Sens. Lindsey Graham of South Carolina and Kelly Ayotte of New Hampshire. The addition was essential for getting Senate Armed Services Committee Chairman John McCain (R-Ariz.) to back the overall fiscal blueprint.

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But a procedural requirement tucked away in Budget Chairman Mike Enzi’s (R-Wyo.) budget resolution will make it very hard for the Pentagon to ever get the extra money in the appropriations process.

Republican aides said Monday that a budget “point of order” will apply to the additional money — added to the Overseas Contingency Operations — when senators eventually take up a defense appropriations bill.

That point of order requires at least 60 votes to approve any OCO money in a spending bill beyond what Senate Republicans had included in Enzi’s original budget blueprint, which was $58 billion. So the extra $38 billion approved in committee would almost surely have to withstand the point of order.

Getting those 60 votes on the floor to allow those higher levels won’t be an easy task.

It’s unlikely Democrats would help Republicans reach that threshold — considering they have objected to adding more money for defense without an equal boost to domestic spending. The amendment boosting OCO funds, written by Graham and Ayotte, passed the Budget Committee in a party-line, 12-10 vote.

Defense hawks in both the House and Senate have tried to add OCO money — which is intended for the war in Afghanistan and against the Islamic State of Iraq and the Levant — because that money does not count against spending caps outlined in a 2011 deficit-reduction law. By boosting the OCO budget above $90 billion, the military’s overall budget would be at the same level as the Obama administration’s Pentagon budget request of $612 billion.

The boost in OCO funding has helped secure votes for the budget resolution, which will take up most of Congress’ time this week.

“I do support the budget as written out of the Budget Committee,” Sen. Tom Cotton (R-Ark.) said Monday. “I wish that it had more spending for the base defense budget, but we do spend almost $90 billion on emergency supplemental spending, which will help arrest the immediate slide in readiness for our troops and pilots and so forth.”

An earlier draft of Graham and Ayotte’s amendment, obtained by POLITICO, would have lifted the point of order threshold to $96 billion, which would have helped protect the extra war spending. But that provision was dropped from the final version of the amendment the committee approved last week.

Ayotte played down the importance of the budget point of order, saying that 60 votes would be needed to pass the Defense Appropriations bill with the added war dollars anyway.

“A budget process is one where every member gets to weigh in, and this was important to some members,” Ayotte told POLITICO when asked about the altered amendment. “So we get to the point where we mark up the appropriations bill, we’re going to need 60 votes regardless, but it’s very important that we got the OCO money in terms of increased spending for defense that’s needed given the threats we face around the world.”

Deficit hawks have objected to adding money to the war budget, arguing that while the money doesn’t violate the budget caps, it’s still adding to the deficit. The House has likewise struggled with defense spending. House leaders are currently floating a plan to hold two budget votes, one with the extra war money and one without.

Defense analysts say those issues highlight why the boost to OCO spending is likely to be fleeting, with the actual defense money included in this year’s spending bills much less than what’s in the budget resolutions.

“The budget resolution is just the first step in this marathon, and a lot of members will hold their fire and let the defense bloc have their ‘win’ knowing they’ll take it later when it actually counts,” said Mackenzie Eaglen of the conservative American Enterprise Institute.